Cool, that does the trick. I think I can get away with just a 90 watt psu.

Remember that power sim does not calculate peak power draw, just average draw. If you run over, you'll do it at boot/drive spin up time. That's tipically when the most power is drawn. Keep in mind a laptop drive draw about 4 watts, and regular drive draws about 15. A 7200 rpm drive would probably draw more, especially at spin up. Are you using a full size DVDROM? That's about 21 watts vs. a slim drive at about 5.